A header for an automotive air conditioner evaporator requires a generally rectangular in cross section header region having openings cut to receive lateral tubes, a plug closing one end, and a cylindrical opening for connection to an input or output tube at the other end. Such a header was initially made from an aluminum extrusion that accurately conformed to the generally rectangular cross-sectional shape of the header region, and the cylindrical end of the header was separately formed of aluminum and brazed onto the rectangular end of the extrusion. Now, for a cheaper and better header than the brazing operation can produce, the cylindrical end is formed by expanding and rounding an end region of the rectangular extrusion. This requires several hits or presses with different shaped tools, against both inside and outside surfaces, to form the rectangular extrusion into a cylindrical end. The result is a rough and irregular header disfigured by tool marks and priced relatively high to cover the cost of the several stamping operations required.
I have found a simpler, cheaper, and more effective way of making such a header for an automotive air conditioner evaporator. My method of making this part forms it rapidly from a single piece of aluminum tubing in a simple forming operation that produces a smoother and better looking part meeting all the dimensional requirements. Equally important for automotive purposes, my way of making the part can produce it at a lower cost than either of the previous ways.